Accommodation is a process by which the eye adjusts its focal distance to maintain focus on objects of varying distance. Accommodation is a reflex action, but can be consciously manipulated. Accommodation is controlled by contractions of the ciliary muscle. The ciliary muscle encircles the eye's elastic lens and, when contracted, relieves tension applied to the lens via the zonules, causing the lens to relax, change shape, and thus alter its optical power.
As an individual ages, accommodation degrades due to physiological changes in the lens and surrounding tissues. Presbyopia is a progressive age-related loss of accommodative or focusing strength of the eye, which results in increased blur at near distances. This loss of accommodative strength with age has been well studied and is relatively consistent and predictable. Presbyopia affects nearly 1.7 billion people worldwide today (110 million in the United States alone) and that number is expected to substantially rise as the world's population ages.
Recent technologies have begun to provide for various devices that operate in or on a human eye to aid the visual focus of a user. Devices intended to aid in accommodation may take the form of an intraocular lens (IOL), contact lens, or corneal inlay. An electro-active accommodating lens in any of these configurations may include one or more elements and circuitry to apply an electrical signal to change a focusing power of the one or more elements. As successive generations of integrated circuitry continue to scale down in size and power consumption, there is expected to be an increased demand for additional functionality to be incorporated in medical devices such as accommodation-capable (or other) ophthalmic implants. Meeting this demand is constrained by the size of the human eye, which limits the amount of space available for an intraocular device to provide communication, sensor, power and/or other functionality.